Follow the "Steps to send an email notification when an Account Update record is deleted/rejected" doc to create a flow for the Delete button. When you delete the submitted details/record from the salesforce your client will get a notification email on their registered email address so they can fill in the correct details.


P.S. Discover Update Client Details, the easy way to keep client information up to date in Salesforce. Find it on AppExchange - https://appexchange.salesforce.com/appxListingDetail?listingId=a0N3A00000EcsATUAZ